English to Chinese Tech/Engineering Electronics / Elect Eng

Be careful when specifying amperage and delay parameters for the branch circuit breaker that provides power to the PDU. Selection of circuit breakers in an electrical power system should be specified so that when an abnormal condition exists, the breaker closest to the abnormality in the distribution path trips before the larger upstream circuit breaker. This isolates and ***limits service interruption*** only to the branch experiencing the problem.
最后一句的意思好像是：这样只隔离出现问题的分路并限制其断电，但是感觉上又有些不对，出现问题了应该是断开，怎么还限制，不知道是不是意思理解错误了，谢谢。